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I know the 351 build topic has been discussed a lot. I've done a lot of reading but want to try to get all the info in one place to compare options.
I've got a 351 block with a rotating assembly and heads out of a '74 that needs one of everything else. I'm looking for a sporty street truck that will be good on the highway and around town. Maybe in the 350-400 horses and similar torque numbers with good low end torque to get away from a light and make a pass on the highway.
I understand that heads make the largest impact on what numbers will be attainable. But also are largest cost. I see the AFR heads recommended a lot and for good reason. However they are quite pricey.
If I stick with stock heads what kind of performance would I realistically be looking at? Or what would be some good alternative options? I see the gt40 thrown around a lot as well.
I think I'm looking for something in the ballpark of a 513 lift cam with 218/224 duration and would likely stay with a 1.6 rocker arm and something like an edlebrock performer intake and holley 650 carb. I'll likely end up with somewhere around a 315/50/17 or 275/55/17 rear tire. Currently running a 235/75/15
Will be bolted to a c4 transmission for now. Need to determine what rear gear I currently have and what would be best for this application
To get into that power range you need heads with AFR185 like airflow, so while there are options it's still going to cost good money. What are the casting numbers on the '74 heads you have? The early windsor heads were roughly equivalent to a modern GT40 but the smog era started in '74/75 and the heads created in those years are only useful as boat anchors. Here is one of the largest comparison charts I have ever found, it doesn't include all the Ford heads ever made but it will illustrate the differences.
I'll check the casting number on the heads tonight after work.
When you say "AFR 185 airflow" are you referring just to 185 port size and 58cc combustion chamber or more specifically something special about how air flows through those heads?
When you say "AFR 185 airflow" are you referring just to 185 port size and 58cc combustion chamber or more specifically something special about how air flows through those heads?
Its all about airflow because an engine is essentially just an air pump, so head airflow determines HP potential. Port volume is somewhat linked but by itself really doesn't say anything about how well a head works. A good example of that is the chinese World Sr head, ports are the roughly same size but flow quite a bit less.
I'm assuming my heads are 74 smoggers. Just for the sake of argument, what sort of performance do you think could be achieved with a set of GT40 or other similarly priced heads?
I saw in another thread that you recommended the Racing Head Services RHS-35304-01 and had a dyno readout of a stock bottom end with those heads, comp 35-420-8 roller cam, and edlebrock performer rpm airgap that was showing a peak of about 425 torque and just over 400 hp.
It looks like if you can find those heads anywhere they can be had for just over $1k for a set. What are your thoughts there vs the AFR 185s?
I will say I'll be going with a hydraulic flat tappet in my build
Those heads had one of the best performce/dollar ratios at that time and were in the same performance ballpark as the "as cast" AFR heads. I had a set of 180cc Dart Iron Eagles at one time but looking at the web site now it doesn't seem like they offer it for the Windsor motors anymore.
